To further expound: I have heard of this issue many times. Platinum when not correctly or well cast can cause porousity in the metal. It's shown usually with pitting, sometimes fissures. When a pit is hit just right, or a weaker spot in the casting, it will spread. The wedding band issues I had with this were because they were not well cast, most likely rushed to get them out of the office faster, even if they weren't correctly made.
I have not had this issue much with engagement ring settings, any of my solitaire settings. This is the first one that was "cast" and not die struck.
My "lifestyle" includes very little wear of a ring. I rarely wear an e-ring or even a plain band when I am working with my hands, and when I have a ring on my left hand is considered unusable for anything more than typing, random writing or holding a drink. I often take my rings off to eat, just to prevent any whacks, or any dunks. I am perfectly capable of wearing platinum in my "lifestyle". I know a lot about jewelry and metal, and I know what will work for my "lifestyle". If my ring was made well, I wouldn't have this issue.